In the tinder-dry U.S. West, where campfires, fireworks and even lit cigarettes are banned across public lands, another fire-starting culprit remains free of most restrictions: guns.

This year, officials believe target shooting or other firearms use have sparked at least 21 wildfires in Utah and nearly a dozen in Idaho. Shooting is also believed to have caused fires in Arizona, Nevada and New Mexico.

Officials have been asking the public to scale back shooting as legions of firefighters contend with one of the busiest and most destructive wildfire seasons to ever hit the West.

But many in the region avid proponents of the Second Amendment right to bear arms, so most state lawmakers are hesitant to enact any formal restrictions.

"We're not trying to pull away anyone's right to bear arms. I want to emphasize that," said Louinda Downs, a county commissioner in fire-prone Davis County, Utah. "We're just saying, target practice in winter. Target practice on the gun range. When your pleasure hobby is infringing or threatening someone else's right to have property or life, shouldn't we be able to somehow have some authority so we can restrict that?"

The state's Republican Gov. Gary Herbert took the unusual step of authorizing the top state forest official to impose gun restrictions on public lands after a gunfire-sparked fire. Herbert said his decision doesn't limit gun rights, but is a common-sense response to dry conditions.

Guns rights advocates are skeptical that firearms use can cause so many wildfires.

Clark Aposhian, chairman of the Utah Sports Shooting Council, said that perhaps 5 percent of the wildfires in the state have been caused by target shooters this year.

Officials believe steel-jacketed bullets are the most likely culprits. One shot that hits a rock and throws off sparks can ignite surrounding vegetation and quickly spread. Popular exploding targets are also blamed for causing wildfires.

For weeks, state officials have said they were powerless to ban gun use because of Second Amendment rights, but legislative leaders say they found an obscure state law that empowers the state forester to act in an emergency.

Among the recent fires, target shooters on June 21 ignited a blaze south of Salt Lake City that forced the evacuation of about 2,300 before it was contained.

Aposhian said his group will conduct tests to determine if the steel-jacketed bullet theory is true. If there are limits, "we want to make sure it is not knee-jerk legislation to ban guns or ammunition," he said. "If it turns out the problem is with a few types of rounds, we will not be an apologist for them."

There is no need for such tests, Utah state fire marshal Brent Halladay said. With steel bullets, "you might as well just go up there and strike a match," he said.

Statistics on wildfires caused by firearms are incomplete because the federal government does not list "shooting" as a cause on its fire reports. But some officials write in "target" or "shoot" as a cause, said Jennifer Jones of the National Interagency Fire Center in Idaho.

On land managed by the U.S. Forest Service only, the center found 17 such wildfires in 2010, 28 last year and 13 so far this year.

This year, the federal Bureau of Land Management said 11 of 31 wildfires it has battled in Idaho have been sparked by shooting activities.

Officials at Arizona's Tonto National Forest had seven wildfires caused by firearms in 2010, 10 in 2011 and at least five so far this year. The potential for fire is so great that shooting for several years has been prohibited on BLM property in the Phoenix area.

In one case in the state, prosecutors said five friends at a campout and bachelor party set off a fire on May 12 when one loaded an incendiary shell, which burns rapidly and causes fires, into a shotgun and pulled the trigger.

Meanwhile, firefighters are wary of more wildfires with the arrival of the Independence Day holiday on July 4.

"Many people use these times to show patriotism as well as support for the Second Amendment," Aposhian said.Associated Press writers Felicia Fonseca and Susan Montoya Bryan contributed to this report. Skoloff reported from Salt Lake City.